The larger pincount packages such as the ADuC7026 and ADuC7027 offer the user the ability to add up to 1MB of external memory to the part. The external memory can either be FLASH or SRAM and can be configured as an 8-bit or 16-bit memory. This memory is mapped as 4 banks, each of which can be 256kB in size. This is accomplished by having 4 memory select lines and a 17-bit address bus.